/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 * 
 *      http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.naming.resources;

import java.io.IOException;
import java.net.URL;
import java.net.URLConnection;
import java.net.URLStreamHandler;
import java.util.Hashtable;

import javax.naming.directory.DirContext;

/**
 * Stream handler to a JNDI directory context.
 * 
 * @author <a href="mailto:remm@apache.org">Remy Maucherat</a>
 * @version $Revision: 467222 $
 */
public class DirContextURLStreamHandler extends URLStreamHandler {

	// ----------------------------------------------------------- Constructors

	public DirContextURLStreamHandler() {
	}

	public DirContextURLStreamHandler(DirContext context) {
		this.context = context;
	}

	// -------------------------------------------------------------- Variables

	/**
	 * Bindings class loader - directory context. Keyed by CL id.
	 */
	private static Hashtable clBindings = new Hashtable();

	/**
	 * Bindings thread - directory context. Keyed by thread id.
	 */
	private static Hashtable threadBindings = new Hashtable();

	// ----------------------------------------------------- Instance Variables

	/**
	 * Directory context.
	 */
	protected DirContext context = null;

	// ------------------------------------------------------------- Properties

	// ----------------------------------------------- URLStreamHandler Methods

	/**
	 * Opens a connection to the object referenced by the <code>URL</code>
	 * argument.
	 */
	protected URLConnection openConnection(URL u) throws IOException {
		DirContext currentContext = this.context;
		if (currentContext == null)
			currentContext = get();
		return new DirContextURLConnection(currentContext, u);
	}

	// ------------------------------------------------------------ URL Methods

	/**
	 * Override as part of the fix for 36534, to ensure toString is correct.
	 */
	protected String toExternalForm(URL u) {
		// pre-compute length of StringBuffer
		int len = u.getProtocol().length() + 1;
		if (u.getPath() != null) {
			len += u.getPath().length();
		}
		if (u.getQuery() != null) {
			len += 1 + u.getQuery().length();
		}
		if (u.getRef() != null)
			len += 1 + u.getRef().length();
		StringBuffer result = new StringBuffer(len);
		result.append(u.getProtocol());
		result.append(":");
		if (u.getPath() != null) {
			result.append(u.getPath());
		}
		if (u.getQuery() != null) {
			result.append('?');
			result.append(u.getQuery());
		}
		if (u.getRef() != null) {
			result.append("#");
			result.append(u.getRef());
		}
		return result.toString();
	}

	// --------------------------------------------------------- Public Methods

	/**
	 * Set the java.protocol.handler.pkgs system property.
	 */
	public static void setProtocolHandler() {
		String value = System.getProperty(Constants.PROTOCOL_HANDLER_VARIABLE);
		if (value == null) {
			value = Constants.Package;
			System.setProperty(Constants.PROTOCOL_HANDLER_VARIABLE, value);
		} else if (value.indexOf(Constants.Package) == -1) {
			value += "|" + Constants.Package;
			System.setProperty(Constants.PROTOCOL_HANDLER_VARIABLE, value);
		}
	}

	/**
	 * Returns true if the thread or the context class loader of the current
	 * thread is bound.
	 */
	public static boolean isBound() {
		return (clBindings.containsKey(Thread.currentThread()
				.getContextClassLoader()))
				|| (threadBindings.containsKey(Thread.currentThread()));
	}

	/**
	 * Binds a directory context to a class loader.
	 */
	public static void bind(DirContext dirContext) {
		ClassLoader currentCL = Thread.currentThread().getContextClassLoader();
		if (currentCL != null)
			clBindings.put(currentCL, dirContext);
	}

	/**
	 * Unbinds a directory context to a class loader.
	 */
	public static void unbind() {
		ClassLoader currentCL = Thread.currentThread().getContextClassLoader();
		if (currentCL != null)
			clBindings.remove(currentCL);
	}

	/**
	 * Binds a directory context to a thread.
	 */
	public static void bindThread(DirContext dirContext) {
		threadBindings.put(Thread.currentThread(), dirContext);
	}

	/**
	 * Unbinds a directory context to a thread.
	 */
	public static void unbindThread() {
		threadBindings.remove(Thread.currentThread());
	}

	/**
	 * Get the bound context.
	 */
	public static DirContext get() {

		DirContext result = null;

		Thread currentThread = Thread.currentThread();
		ClassLoader currentCL = currentThread.getContextClassLoader();

		// Checking CL binding
		result = (DirContext) clBindings.get(currentCL);
		if (result != null)
			return result;

		// Checking thread biding
		result = (DirContext) threadBindings.get(currentThread);

		// Checking parent CL binding
		currentCL = currentCL.getParent();
		while (currentCL != null) {
			result = (DirContext) clBindings.get(currentCL);
			if (result != null)
				return result;
			currentCL = currentCL.getParent();
		}

		if (result == null)
			throw new IllegalStateException("Illegal class loader binding");

		return result;

	}

	/**
	 * Binds a directory context to a class loader.
	 */
	public static void bind(ClassLoader cl, DirContext dirContext) {
		clBindings.put(cl, dirContext);
	}

	/**
	 * Unbinds a directory context to a class loader.
	 */
	public static void unbind(ClassLoader cl) {
		clBindings.remove(cl);
	}

	/**
	 * Get the bound context.
	 */
	public static DirContext get(ClassLoader cl) {
		return (DirContext) clBindings.get(cl);
	}

	/**
	 * Get the bound context.
	 */
	public static DirContext get(Thread thread) {
		return (DirContext) threadBindings.get(thread);
	}

}
